Blender started lagging when using more (single) bones
Had a similar problem, but not with rigging. Check the size of your .blend file and see if it seems too large for your average model. I once made a simple hanger for clothes and it's size was over 15mb. I deleted few objects and managed to find out what was causing it.
If your file seems too large, try deleting the object/bone that makes blender lagspike the most when you select it and save the file somewhere to see if that fixed it.

PS: wanted to comment, but you apparently need 50 points to do that...